1. Field of the invention
The present invention relates to the field of transmission engineering. In particular, it relates to a coaxial antenna selector comprising
a plurality of coaxial input lines for feeding in an RF power of corresponding transmitters; PA1 a plurality of coaxial output lines for delivering the RF power to corresponding antennas; PA1 each input line being optionally connectable to each output line. PA1 each input line and each output line is in each case associated with a single moving link element in form of a coaxial line; which coaxial line PA1 is connected with the one line end to the associated input and output line; and PA1 can be displaced along an associated displacement line with the other open line end; in such a manner that PA1 each displacement line of a link element associated with an input line intersects all displacement lines of the link elements associated with the output lines.
Such an antenna selector is known, for example, from EP-B1 0 044 099.
2. Discussion of background
In large-scale broadcasting transmission systems, particularly in the short-wave field, a plurality of independently operating individual transmitters is used which radiate the amplitude-modulated carrier signal via different antennas depending on the time of day and the program.
The RF power which in most cases is within the range of several 100 kW is fed into the respective antenna from the respective transmitter via coaxial lines (50 ohm) with high ratings.
To provide the possibility of rapidly and flexibly setting up a connection between the individual transmitters and antennas, a coaxial antenna selector is arranged between the two with the aid of which any desired connection between an arbitrary transmitter and an arbitrary antenna can be switched within a short time.
Known coaxial antenna selectors are constructed in accordance with the matrix principle (EP-B1 0 044 099). In these matrix selectors, the input lines coming from the transmitters form the rows and the output lines going off to the antennas form the columns of a matrix.
At the nodes of the matrix, coaxial change-over switches are arranged in pairs which connect through the respective row or column line in one switch position and disconnect both lines and connect diagonally in the node in the other switch position.
It follows from this, on the one hand, that in the case of n transmitters and m antennas, that is to say in the case of an (n.times.m) matrix, 2.times.n.times.m change-over switches are needed, all of which require a separate drive and separate control.
On the other hand, the diagonal switching-over leaves in the antenna selector of the conventional type lines with open ends in which high voltages can be induced during operation which lead to interference in the system if not additional countermeasures are taken (so-called crosstalk).
Finally, the large number of change-over switches which are located in a switched-through connection leads to a correspondingly large number of contact points in the line connection which naturally represent weak points.